beginner help - thorens td 125 mk2 - Page 3 - diyAudio
Go Back   Home > Forums > Source & Line > Analogue Source

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 2nd January 2012, 06:29 PM   #21
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
The arm is in no way associated with any of the electronics in this table, and when you slide the power switch to the right the motor should start immediately and run at the speed selected. It should come up to speed within one revolution or so if everything is working correctly. I would expect at a minimum that this unit needs to have all of the electrolytics replaced as well as switch contacts cleaned. There may be other problems.. To do the repairs on this table properly you will need a good soldering iron, DVM and an oscilloscope.
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 2nd January 2012, 06:33 PM   #22
diyAudio Member
 
Join Date: Dec 2011
Ok thanks. I have somewhere to start now, however looking at the service manual i think i will need further instruction or help to fix this :-/
  Reply With Quote
Old 2nd January 2012, 06:39 PM   #23
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Quote:
Originally Posted by langers2004 View Post
Ok thanks. I have somewhere to start now, however looking at the service manual i think i will need further instruction or help to fix this :-/
I'll help where I can.. The end result is definitely worth the effort.. Just start with small things like cleaning the switch contacts, and measuring voltages.. I would definitely replace the electrolytics in the supply before proceeding very far, there are others that would also be good candidates for replacement. The manual is fairly good. Vishay and a couple of other companies still make good axial leaded capacitors which if memory serves is what you will require. Hopefully the ICs are all still OK.. I had a MKI for many years before I got my first TD-124 in late 2010..
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 2nd January 2012, 06:50 PM   #24
diyAudio Member
 
Join Date: Dec 2011
Thanks :-) Well firstly im going to try and work out how to take the front plate off as most of the screws seem to be blocked by other things, i havent taken the actual floating section out yet as i wasnt sure how to.

Im hoping if i clean the switches all will be better. I have been told by the original owner that something may be wrong with a component that seats into it. Vague i know, i will try and clarify this.
  Reply With Quote
Old 2nd January 2012, 06:57 PM   #25
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Nope, do NOT remove the front plate.

Take the bottom off of the plinth and remove the mounting screws from the bottom that retain the TT chassis to the plinth.. IIRC there are 4 of them.. Everything is reachable from the bottom side, and if you take the top plate apart there is the extreme likelihood that you will never get it back together.
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 2nd January 2012, 06:59 PM   #26
diyAudio Member
 
Join Date: Dec 2011
Glad i didnt manage it then!

Right ill take the bottom off and see what the inside looks like, ill post some pics in the off chance that helps.
  Reply With Quote
Old 3rd January 2012, 12:06 AM   #27
diyAudio Member
 
Join Date: Sep 2009
Location: Lima, Peru
Hi langers,

Congrats on the TD125MK2. I just refurbished one today and am listening to it right now! It is a wonderful turntable, a classic, one of the best of all times...

HOWEVER, and i don't want to be a bad guy, for the do-it-yourself turntable enthusiast, this is one of the most difficult turntables to repair/get back in good shape. I would advise you to either (a) sell it to another DIY enthusiast or (b) arm yourself with time and patience because you will need it.

Now, i'm assuming you choose alternative (b)

Let me do a quick checklists of what you have to do. First, does the motor turn? does the turntable spin and the stroboscope lights up showing the speed is reasonably stable ? I'll assume "YES".

So this is standard manteinance for the TD125MK2:

1. Remove bottom cover.
2. Unscrew the control circuit board (2 screws) and replace the two big 1000uF capacitors. Be sure to put the new ones in the correct polarity. 1000, 2000, 3300uF capacitors will work OK, the bigger the better. They should be 25V or 50V rating.

3. Be sure that the top plate (the one that "floats") is level. You can use a bubble level to check. If it isn't level, on the underside of the turntable there are three white "knobs" that you can turn to raise/lower the suspended part of the turntable.

4. Now i assume that if you turn on the turntable, it spins at 33RPM correctly, i.e. the stroboscope marks stand reasonably still. If they wobble too much or don't reach correct speed (despite the turntable belt is correctly located on the motor spindle), then do the voltage/speed adjustment detailed in the service manual.

5. Once the turntable is level you must make sure the motor spindle is level too. For this, there is a screw that controls the azimuth of the motor. It is visible if you take out the outer platter. It has some enamel applied at the factory (so it doesn't move). Remove the outer platter and turn the turntable on. The inner platter will spin. Now stop the inner platter with your hand and check what happens to the belt in the motor spindle. If it goes UP, then you need to turn that screw counter-clockwise. If it goes DOWN then you need to turn the screw clockwise.

Now put the outer platter on and do the same test (stop the outer platter with your hand). Then verify that the belt does not go out of the correct motor pulley section. Correct the azimuth screw as necessary.

6. You may want to clean the switch contacts in the control circuit board. As mentioned before, DO NOT REMOVE THE FRONT PLATE. There is no need to do it and it's a very difficult procedure.

7. The main bearing. You want it to spin freely without making any noise. Try draining the lubricant and cleaning it with solvent. Clean the inner platter spindle (in other words the bearing spindle) using metal polish paste. It should shine as new.

Pour light machine oil (i.e. 3-in-1 oil) on the bearing reservoir. Pour a lot of oil. When pushing the spindle in, if you push in quickly, the excess oil will force the brass bearing bushings to pop out. Then you have a great opportunity to clean them with some solvent.

To correctly reassemble the bearing, push the spindle gently, softly, until it slowly enters the bearings without popping out the bronze bushings.

It is VERY IMPORTANT to have the inner platter spin freely and with no kind of noise at all (you need to be in a silent room to check this). Unless you don't want to bring out the audiophile sound of the TD125!!

What else? The arm... The arm is wired as any other arm. It's effective arm mass is 10g. It is a good arm so treat it carefully.

The cartridge is compatible with the Audio-Technica AT95E, there are a lot of needles available.
  Reply With Quote
Old 3rd January 2012, 12:12 AM   #28
diyAudio Member
 
Join Date: Sep 2009
Location: Lima, Peru
Also, there's a light bulb in the control circuit. This is a *critical* component of the control circuit, if it's broken, the turntable will not work. So Don't mess with it! Don't touch it! Don't even look at it !! If the motor spins then the light bulb is OK. What i mean is: Be careful not to break the light bulb.

If the motor does not turn or it turns irregularly (or makes noises), then the control circuit is faulty. Assuming the switch contacts are clean and that the power capacitors (1000uF) have been replaced and that the light bulb conducts current (use a digital multimeter to check it)... Then the part that might be faulty are the power transistors (4) and -least likely- the opamps. The Opamps are model 709c (outdated, older than my grandma), and can be replaced with the very common 741 opamp IF YOU KNOW WHAT YOU ARE DOING... which means, if you go to the Vinylengine forum and search more about this substitution.

Cheers!

PS: Any problem with the turntable motor not spinning or not spinning correctly is 99% fault of the control circuit board. Don't be tempted with replacing the motors. Those motors do not fail, they are German products of the highest caliber, straight from the Gods.
  Reply With Quote
Old 3rd January 2012, 12:16 AM   #29
diyAudio Member
 
Join Date: Sep 2009
Location: Lima, Peru
Quote:
Originally Posted by grufti View Post
the 125mk2 with its original arm will lower the arm at the push of one of its buttons and raise it at the end of the record.
That's the TD126 or the TD145, not the TD125. The 125 is fully manual.

The electronics on the 125 / 125MKII are essential to the turntable. Nothing to be bypassed.

Last edited by flavio81; 3rd January 2012 at 12:32 AM.
  Reply With Quote
Old 3rd January 2012, 12:19 AM   #30
diyAudio Member
 
Join Date: Sep 2009
Location: Lima, Peru
Quote:
Originally Posted by kevinkr View Post
Please make sure that the power transformer is actually wired for your local mains voltage if it did not come from a UK/European seller
Yes, very important!! On the bottom of the turntable there is a small circuit board covered by a big black cover. If you take out the cover you will see the mains fuse. The fuse can be placed in 2 different sockets, one is for 220V the other for 110V so double check!!

If it was at 110V and you connected it to 220V, some electronic components may be damaged... You will need then to replace the power transistors (4), the ICs (2) and the power supply capacitors (2), plus maybe the rectifier diode bridge (1). The motor will probably be fine.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
FS: SME armboard from my Thorens TD 125 mk2 johnnyk9 Swap Meet 1 8th December 2011 04:06 AM
Beginner Help: Thorens TD 125 voltage chrisnewton Analogue Source 3 15th September 2010 03:32 AM
cartridge for thorens td-125 maxpou Analogue Source 9 20th January 2010 01:06 AM
Thorens TD 125 with SME 3012 Karrry Everything Else 14 30th April 2009 02:58 PM
Thorens TD-125 Ken(Toronto) Analogue Source 3 31st March 2008 09:41 AM


New To Site? Need Help?

All times are GMT. The time now is 09:32 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2